我被分配了这个家庭作业，我一直很难做到。表格已经写好了，我们必须写课程。目前，当我运行程序时，我的等号按钮似乎不起作用。我不确定为什么，我想知道是否有人可以帮助我了解我所缺少的。我相信我已经正确地写了我的课。在我的脑海中，计算器正在调用“currentValue”，所以我不断更新我在运算符中使用的方法。
我在正确的方向吗？
为什么我的等号按钮不调用当前值。上次我运行这个时，如果我输入 9 + 3 +，那么我的显示屏将填充 12 并等待我输入下一个数字。所以理论上为什么我的等号按钮不能加载答案？我相信我正在调用正确的项目，但我不断收到我的初始条目。例如，如果我输入 9 + 9 并点击 =，我会一直得到 9。
这是计算器代码（提供的部分）：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace Calculator
{
public partial class frmCalculator : Form
{
public frmCalculator()
{
InitializeComponent();
}
// The following fields are used to store the value that's currently
// displayed by the calculator. displayString is a string value that's
// constructed as the user clicks numeric keys and the decimal and +/-
// key. The Convert.ToDecimal method is then used to convert this to a decimal
// field that's stored in displayValue.
private string displayString;
private decimal displayValue;
// The following bool fields are used to control numeric entry.
// newValue indicates whether the calculator is ready to receive a
// new numeric value. Once the user clicks a digit button, newValue is
// set to false. When the user clicks a button that "enters" the value,
// such as Add or Equals, newValue is set to true so the user can enter
// another value.
// decimalEntered is used to restrict the entry to a single decimal point.
// It is set to true whenever newValue is set to true, and it is set to
// false whenever the user clicks the decimal point button.
private bool newValue;
private bool decimalEntered;
private Calculator calc = new Calculator();
private void Form1_Load(object sender, System.EventArgs e)
{
displayValue = 0;
displayString = displayValue.ToString();
newValue = true;
decimalEntered = false;
}
// This method handles the 0 through 9 keys, appending the digit clicked
// to the displayString field.
private void btnNumber_Click(object sender, System.EventArgs e)
{
if (newValue)
{
displayString = "";
newValue = false;
}
displayString += ((Button)sender).Tag.ToString();
displayValue = Convert.ToDecimal(displayString);
txtDisplay.Text = displayValue.ToString();
}
// This method removes the last character from the displayString field.
private void btnBackSpace_Click(object sender, System.EventArgs e)
{
if (displayString.Length > 1)
{
displayString = displayString.Substring(0, displayString.Length - 1);
displayValue = Convert.ToDecimal(displayString);
txtDisplay.Text = displayValue.ToString();
}
else
{
displayString = "";
displayValue = 0;
txtDisplay.Text = displayValue.ToString();
}
}
private void btnClear_Click(object sender, System.EventArgs e)
{
calc.Clear();
displayString = "";
displayValue = 0;
txtDisplay.Text = displayValue.ToString();
newValue = true;
decimalEntered = false;
}
// This method appends a decimal point to the displayString field if the
// user has not already entered a decimal point.
private void btnDecimal_Click(object sender, System.EventArgs e)
{
if (newValue)
{
displayString = "0";
newValue = false;
}
if (!decimalEntered)
{
displayString += ".";
displayValue = Convert.ToDecimal(displayString);
txtDisplay.Text = displayValue.ToString();
decimalEntered = true;
}
}
private void btnSign_Click(object sender, System.EventArgs e)
{
displayValue = -displayValue;
txtDisplay.Text = displayValue.ToString();
}
private void btnAdd_Click(object sender, System.EventArgs e)
{
calc.Add(displayValue);
newValue = true;
decimalEntered = false;
displayValue = calc.CurrentValue;
txtDisplay.Text = displayValue.ToString();
}
private void btnSubtract_Click(object sender, System.EventArgs e)
{
calc.Subtract(displayValue);
newValue = true;
decimalEntered = false;
displayValue = calc.CurrentValue;
txtDisplay.Text = displayValue.ToString();
}
private void btnMultiply_Click(object sender, System.EventArgs e)
{
calc.Multiply(displayValue);
newValue = true;
decimalEntered = false;
displayValue = calc.CurrentValue;
txtDisplay.Text = displayValue.ToString();
}
private void btnDivide_Click(object sender, System.EventArgs e)
{
calc.Divide(displayValue);
newValue = true;
decimalEntered = false;
displayValue = calc.CurrentValue;
txtDisplay.Text = displayValue.ToString();
}
private void btnSqrt_Click(object sender, System.EventArgs e)
{
calc.SquareRoot(displayValue);
displayValue = calc.CurrentValue;
txtDisplay.Text = displayValue.ToString();
}
private void btnReciprocal_Click(object sender, System.EventArgs e)
{
try
{
calc.Reciprocal(displayValue);
displayValue = calc.CurrentValue;
txtDisplay.Text = displayValue.ToString();
}
catch (DivideByZeroException)
{
displayValue = 0;
txtDisplay.Text = "Cannot divide by zero.";
newValue = true;
decimalEntered = false;
}
}
private void btnEquals_Click(object sender, System.EventArgs e)
{
try
{
if (newValue)
calc.Equals();
else
calc.Equals(displayValue);
displayValue = calc.CurrentValue;
txtDisplay.Text = displayValue.ToString();
newValue = true;
decimalEntered = false;
}
catch (DivideByZeroException)
{
displayValue = 0;
txtDisplay.Text = "Cannot divide by zero.";
newValue = true;
decimalEntered = false;
}
}
}
}
这是我的课（我写的部分）：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Calculator
{
public class Calculator
{
public Decimal displayValue;
public Decimal currentValue;
public void Add(Decimal displayValue)
{
currentValue += displayValue;
}
public void Subtract(Decimal displayValue)
{
currentValue -= displayValue;
}
public void Multiply(Decimal displayValue)
{
currentValue *= displayValue;
}
public void Divide(Decimal displayValue)
{
currentValue /= displayValue;
}
public void SquareRoot(Decimal displayValue)
{
currentValue = (decimal)Math.Sqrt(Convert.ToDouble(displayValue));
}
public void Reciprocal(Decimal displayValue)
{
currentValue = 1 / displayValue;
}
public decimal Equals()
{
return currentValue;
}
public void Clear()
{
currentValue = 0;
displayValue = 0;
}
public decimal CurrentValue
{
get
{
return currentValue;
}
}
}
}